CN103188182A - Frequency spectrum estimation method based on fast variable Doppler channel and frequency spectrum estimation device - Google Patents
Frequency spectrum estimation method based on fast variable Doppler channel and frequency spectrum estimation device Download PDFInfo
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Abstract
The invention discloses a frequency spectrum estimation method based on a fast variable Doppler channel and a frequency spectrum estimation device. The frequency spectrum estimation method includes the following steps: whether the serial number of a second sub-frame in a second sub-frame group corresponds to the serial number of a first sub-frame in a first sub-frame group is judged, wherein the first sub-frame group and the second sub-frame group are two sub-frame groups which are arbitrarily chosen from currently received sub-frame groups, each sub-frame group is composed of multiple sub-frames, and the number of the sub-frames in each sub-frame group is predetermined; if the judging result is yes, the frequency deviations of the other sub-frames, which are received currently, except the first sub-frame and the second sub-frame are calculated according to the linear interpolation algorithm; and if the judging result is no, the frequency deviations of all the sub-frames which are received currently are calculated. Through the frequency spectrum estimation method based on the fast variable Doppler channel and the frequency spectrum estimation device, the accuracy of a frequency spectrum estimation of the fast variable Doppler channel in a high-speed rail environment can be improved, and therefore the effect of improving the performance and the working efficiency of a wireless communication is achieved.
Description
Technical field
The present invention relates to the communications field, in particular to a kind of spectrum estimating method and device based on fast change Doppler channel.
Background technology
In recent years, the progress of the high-speed railway of China (hereinafter to be referred as " high ferro ") complete set technology is highly visible, and high ferro has become national significant achievement.At present, China has become the country that Development of High Speed Railway is the fastest in the world, systems technology is the most complete, integration capability is the strongest, the operation mileage is the longest, the speed of service is the highest, building scale is maximum.
The high ferro wireless communications environment is complicated and changeable, typical geographical environments such as experience Plain, mountain area, tunnel, U-shaped groove.Simultaneously, different with the hexagon honeycomb of public correspondence net, the coverage that the high-speed railway broadband wireless access covers is zonal distribution along railway, different scenes shows different wireless fading channel features, wherein, bullet train passes through in the process of base station, shows typical single fast Doppler of change in footpath (Doppler) decline.When the wireless transmission centre frequency be 2.1GHz, when movement velocity reaches 360km/h, Doppler frequency deviation will reach 700Hz, because the close together (about 20-50 rice) of communication base station and railway, when train crosses communication base station at a high speed, Doppler frequency deviation will change to minimum (the most negative) fast from maximum (the most just), and channel is quick time-varying characteristics.
3GPP (Third Generation Partnership Project, third generation partner program) the high ferro radio environment of definition mainly contains two kinds of Plain model and tunnel models in, the common ground of two models all is the non-fading channel that has Dan Jing, but the wireless channel of this Dan Jing is subjected to periodically variable Doppler frequency shift modulation.
Doppler frequency shift is represented with following formula: f
s(t)=f
dCos θ (t), wherein, f
dExpression maximum doppler frequency .f
s(t) expression is because the mobile Doppler frequency shift that causes is represented the angle between θ (t) direct-view footpath and the train direction of motion, at existing high ferro TD system group network characteristics, f
sBe cyclic variation.As follows according to its cosine value representation of easy release:
cosθ(t)＝cosθ(tmod(2D
s/v))，t＞2D
s/v；
Wherein: D
s/ 2 expression bullet trains are apart from the lateral separation of base station, and unit is m;
D
MinThe vertical range of expression base station and rail, unit is m;
V represents the speed (m/s) of train;
T represents Train Schedule (s).
Please refer to Fig. 1 and Fig. 2, Fig. 1 is that as shown in Figure 1, the expression centre frequency is 2.1GHz according to the fast change Doppler's of correlation technique schematic diagram, and train speed is under the situation of 360km/h, and train passes through base station Doppler (Doppler) situation of change constantly.Fig. 2 is the Doppler's linear change schematic diagram according to correlation technique, and as can be seen from Figure 2, in sectional area, Doppler (Doppler) can be considered as linear change.
Simultaneously, the 3GPP tissue has proposed the concept (please refer to Fig. 3, Fig. 3 is the LTE frame structure schematic diagram according to correlation technique) of LTE (Long Term Evolution, Long Term Evolution).LTE has abandoned the CDMA technology that 3G uses, and selects for use OFDM (Orthogonal Frequency Division Multiplexing, OFDM) technology to improve the system bandwidth utilance; And, also adopted MIMO (Multiple-Input Multiple-Output, multiple-input and multiple-output) technology, can be under the prerequisite that does not increase system bandwidth, improve the rate of information throughput, because have above-mentioned advantage, LTE has become the new development direction after the 3G (Third Generation) Moblie standard.But. with respect to single-carrier modulated, ofdm system is more responsive to frequency shift (FS), and along with the increase of subcarrier-modulated exponent number, sensitivity also can increase.Frequency shift (FS) in the ofdm system has reduced the orthogonality between subcarrier, causes inter-carrier interference easily.ICI (Inter Carrier Interference disturbs between subcarrier) can reduce the performance of channel estimating and symbol detection, causes the increase of bit error rate.The LTE system has adopted special synchronizing signal as the scheme of synchronous training sequence, and still, simultaneous techniques can not be eliminated frequency deviation fully to the influence of OFDM, and, becoming under the Doppler channel condition fast, frequency deviation correction is particularly important to the LTE system.
The Frequency Synchronization technology of LTE can remedy the performance loss that fast change Doppler brings to a certain extent, and Frequency Synchronization technology commonly used has autocorrelation technique and cross-correlation technique.Wherein, autocorrelation technique mainly is to utilize CP (Cyclic Prefix, Cyclic Prefix) directly related in time domain, and the peak phase that obtains is carried out Frequency Synchronization, but because CP is shorter, is easy to be subjected to the influence of Doppler and noise jamming; It is relevant that cross-correlation technique mainly adopts the entrained correlated series of LTE and local sequence to carry out, and when frequency shift (FS) surpassed a subcarrier, cross-correlation peak value disappeared, and the precision of Frequency Synchronization is lower.Because bullet train is in passing through the process of base station, Doppler can change rapidly, only depends on simple method for synchronous to estimate that frequency deviation can not guarantee that it is accurate.
Fast change Doppler when simple method for synchronous passes through the base station to bullet train in the correlation technique carries out the coarse problem of spectrum estimation, does not propose effective solution at present as yet.
Summary of the invention
The invention provides a kind of spectrum estimating method and device based on fast change Doppler channel, to address the above problem at least.
According to an aspect of the present invention, a kind of spectrum estimating method based on fast change Doppler channel is provided, comprise: whether the numbering of judging second subframe in the second subframe group is corresponding with the numbering of first subframe in the first subframe group, wherein, the first subframe group and the second subframe group are any two in the current subframe group that receives, and the subframe group is made of the subframe of predetermined number; Be under the situation that is in judged result, the frequency shift (FS) of calculating current other subframes except first subframe and second subframe that receive according to linear interpolation algorithm, judged result for the situation of denying under, the frequency shift (FS) of calculating the current whole subframes that receive.
Preferably, the frequency shift (FS) according to linear interpolation algorithm calculates current other subframes except first subframe and second subframe that receive comprises: calculate the deviation slope between second subframe and first subframe; Receive the frequency shift (FS) of calculating current other subframes except first subframe and second subframe that receive according to the deviation slope.
Preferably, calculate the deviation slope between second subframe and first subframe, comprising: according to channel impulse response CIR first subframe and second subframe are carried out estimation of deviation, obtain the first frequency skew of first subframe and the second frequency skew of second subframe; According to first frequency skew and second frequency calculations of offset deviation slope.
Preferably, according to channel impulse response CIR first subframe is carried out estimation of deviation, comprising: from first subframe, extract the reference signal in any two orthogonal frequency division multiplex OFDM symbols that comprise reference signal; Obtain a CIR and the 2nd CIR of two OFDM symbols in first subframe respectively according to reference signal; According to a CIR and the 2nd CIR first subframe is carried out estimation of deviation.
Preferably, obtain a CIR and the 2nd CIR of two OFDM symbols in first subframe respectively according to reference signal, comprising: reference signal is carried out lowest mean square LS estimate; The reference signal that will obtain after will estimating through LS transforms on the time domain; Obtain a CIR and the 2nd CIR respectively according to the reference signal that transforms on the time domain.
Preferably, according to channel impulse response CIR second subframe is carried out estimation of deviation, comprising: from second subframe, extract the reference signal in any two orthogonal frequency division multiplex OFDM symbols that comprise reference signal; Obtain the 3rd CIR and the 4th CIR of two OFDM symbols in second subframe respectively according to reference signal; According to the 3rd CIR and the 4th CIR second subframe is carried out estimation of deviation.
Preferably, obtain the 3rd CIR and the 4th CIR of two OFDM symbols in second subframe respectively according to reference signal, comprising: reference signal is carried out lowest mean square LS estimate; The reference signal that will obtain after will estimating through LS transforms on the time domain; Obtain the 3rd CIR and the 4th CIR respectively according to the reference signal that transforms on the time domain.
According to a further aspect in the invention, a kind of frequency shift estimation device based on fast change Doppler channel is provided, comprise: judge module, whether the numbering of second subframe that is used for judging the second subframe group is corresponding with the numbering of first subframe in the first subframe group, wherein, the first subframe group and the second subframe group are any two in the current subframe group that receives, and the subframe group is made of the subframe of predetermined number; Computing module, being used in judged result is under the situation that is, according to the frequency shift (FS) that linear interpolation algorithm calculates current other subframes except first subframe and second subframe that receive, be under the situation not in judged result, the frequency shift (FS) of calculating the current whole subframes that receive.
Preferably, computing module comprises: first computing module is used for calculating the deviation slope between second subframe and first subframe; Second computing module is used for receiving the frequency shift (FS) of calculating current other subframes except first subframe and second subframe that receive according to the deviation slope.
Preferably, first computing module comprises: estimation unit, be used for according to channel impulse response CIR first subframe and second subframe being carried out estimation of deviation, and obtain the first frequency skew of first subframe and the second frequency skew of second subframe; Computing unit is used for according to described first frequency skew and the described deviation slope of described second frequency calculations of offset.
By the present invention, the LTE signal (frame structure) that adopts channel impulse response (CIR) that receiver is received carries out the secondary frequency deviation and estimates, and adopt linear interpolation method to calculate the frequency shift (FS) of LTE subframe, the fast change Doppler that has solved when correlation technique adopts simple method for synchronous that bullet train is passed through the base station carries out the coarse problem of spectrum estimation, and then has reached the performance of raising wireless communication system and the effect of operating efficiency.
Description of drawings
Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used for explaining the present invention, do not constitute improper restriction of the present invention.In the accompanying drawings:
Fig. 1 is the schematic diagram according to the fast change Doppler of correlation technique;
Fig. 2 is the Doppler's linear change schematic diagram according to correlation technique;
Fig. 3 is the LTE frame structure schematic diagram according to correlation technique;
Fig. 4 is the flow chart based on the spectrum estimating method of fast change Doppler channel according to the embodiment of the invention;
Fig. 5 is the spectrum estimation flow chart of Doppler's channel according to the preferred embodiment of the invention;
Fig. 6 is that the linear interpolation Doppler frequency deviation is estimated schematic diagram according to the preferred embodiment of the invention;
Fig. 7 is according to the preferred embodiment of the invention when the LTE bandwidth is 1.4MHZ, centre frequency is 2.1GHZ, it is 0 (awgn channel), 50Hz, 100Hz, 200Hz and 300Hz single-frequency bias energy that channel is respectively Doppler, and carries out the performance schematic diagram after the CIR frequency deviation is estimated;
Fig. 8 is according to the preferred embodiment of the invention when the LTE bandwidth is 1.4MHZ, and centre frequency is 2.1GHZ, and channel is respectively awgn channel and the fast Doppler of change channel performance, and adopts full range to estimate partially and linear segmented frequency deviation estimated performance schematic diagram;
Fig. 9 is the structured flowchart based on the frequency shift estimation device of fast change Doppler channel according to the embodiment of the invention;
Figure 10 is according to the preferred embodiment of the invention based on the structured flowchart of the frequency shift estimation device of fast change Doppler channel.
Embodiment
Hereinafter will describe the present invention with reference to the accompanying drawings and in conjunction with the embodiments in detail.Need to prove that under the situation of not conflicting, embodiment and the feature among the embodiment among the application can make up mutually.
Fig. 4 is the flow chart based on the spectrum estimating method of fast change Doppler channel according to the embodiment of the invention, and as shown in Figure 4, this method mainly may further comprise the steps (step S402-step S404):
Step S402, whether the numbering of judging second subframe in the second subframe group is corresponding with the numbering of first subframe in the first subframe group, wherein, the first subframe group and the second subframe group are any two in the current subframe group that receives, and the subframe group is made of the subframe of predetermined number;
Step S404, be under the situation that is in judged result, according to the frequency shift (FS) that linear interpolation algorithm calculates current other subframes except first subframe and second subframe that receive, be under the situation not in judged result, the frequency shift (FS) of calculating the current whole subframes that receive.
Wherein, in step S404, the frequency shift (FS) according to linear interpolation algorithm calculates current other subframes except first subframe and second subframe that receive comprises: calculate the deviation slope between second subframe and first subframe; Receive the frequency shift (FS) of calculating current other subframes except first subframe and second subframe that receive according to the deviation slope.
In a preferred embodiment of the present invention, calculate the deviation slope between second subframe and first subframe, comprise: according to channel impulse response CIR first subframe and second subframe are carried out estimation of deviation, obtain the first frequency skew of first subframe and the second frequency skew of second subframe; According to first frequency skew and second frequency calculations of offset deviation slope.
Wherein, according to channel impulse response CIR first subframe is carried out estimation of deviation, comprising: from first subframe, extract the reference signal in any two orthogonal frequency division multiplex OFDM symbols that comprise reference signal; Obtain a CIR and the 2nd CIR of two OFDM symbols in first subframe respectively according to reference signal; According to a CIR and the 2nd CIR first subframe is carried out estimation of deviation.In actual applications, obtain a CIR and the 2nd CIR of two OFDM symbols in first subframe respectively according to reference signal, comprising: reference signal is carried out lowest mean square LS estimate; The reference signal that will obtain after will estimating through LS transforms on the time domain; Obtain a CIR and the 2nd CIR respectively according to the reference signal that transforms on the time domain.
Wherein, according to channel impulse response CIR second subframe is carried out estimation of deviation, comprising: from second subframe, extract the reference signal in any two orthogonal frequency division multiplex OFDM symbols that comprise reference signal; Obtain the 3rd CIR and the 4th CIR of two OFDM symbols in second subframe respectively according to reference signal; According to the 3rd CIR and the 4th CIR second subframe is carried out estimation of deviation.In actual applications, obtain the 3rd CIR and the 4th CIR of two OFDM symbols in second subframe respectively according to reference signal, comprising: reference signal is carried out lowest mean square LS estimate; The reference signal that will obtain after will estimating through LS transforms on the time domain; Obtain the 3rd CIR and the 4th CIR respectively according to the reference signal that transforms on the time domain.
In actual applications, at first provide the transmission frame structure of LTE, as: the LTE frame length is 10ms, be divided into 10 subframes, the long 1ms of each subframe, each subframe is divided into two time slots, each time slot comprises 6 or 7 OFDM symbols, subcarrier spacing in the symbol is 15kHz, and conventional CP length is 4.6875us, and expansion CP length is 16.67us.
For example, suppose that the number of sub frames that transmitter sends is Frame_Num, Frame_Num LTE subframe needs to send successively; At receiving terminal, receiver removes CP with the LTE signal that receives, carry out IFFT (Inverse Fast Fourier Transform, inverse fast fourier transform) transforms to frequency domain, to subframe carry out that frequency deviation is estimated and compensation after, again each subframe is carried out LS and estimate and linear interpolation terminal decision.
The spectrum estimating method based on fast change Doppler channel that provides below in conjunction with the embodiment of the invention of Fig. 5 is elaborated.
Fig. 5 is the spectrum estimation flow chart of Doppler's channel according to the preferred embodiment of the invention, and as shown in Figure 5, this flow process may further comprise the steps:
S502, receiver are that unit receives the LTE signal with the subframe, set subframe group Row_Num at receiving terminal, set each subframe group and comprise
Individual subframe judges that by subframe numbering whether the subframe Subframe (i) that receives is first group of subframe receiving or first subframe of each subframe group, that is, if satisfy:
S504 extracts the reference signal in any two OFDM symbols that comprise reference signal among this subframe Subframe (i), carries out transforming to time domain after LS estimates, obtain respectively this subframe in channel impulse response (CIR) h1 and the h2 of two OFDM symbols; As can be known, the time-varying characteristics of channel can characterize with the time-varying characteristics in direct projection footpath or main footpath in conjunction with high ferro channel model feature (the close base station of train is also passed through in the process of base station, and the K factor is bigger);
S506 utilizes two CIR that obtain among the S504 to carry out estimation of deviation, the frequency shift (FS) that obtains as the estimation of this subframe.If:
Then:
The Doppler frequency difference that draws subframe Subframe (i) from above-mentioned formula is:
S508 judges this subframe Subframe (i) by the subframe numbering again, if the numbering among the subframe Subframe (i) satisfies:
I=n*N+1, n=2,3 ... Row_Num-1 then carries out S510, otherwise, forward S514 to;
S510 calculated the straight slope of point (that is: second subframe) (Subframe (i-N), Freq_estimation (Subframe (i-N))) and point (that is: first subframe) (Subframe (i), Freq_estimation (Subframe (i)))
And linear interpolation;
S512 utilizes the frequency difference slope Freq_slope and the linear interpolation that obtain among the S510 to calculate subframe Subframe (k) respectively, k=i+1, and i+2 ... the frequency deviation of i+N-1:
Freq_estimation(Subframe(k))＝Freq_slope*(Subframe(k)-Subframe(i))+
Freq_estimation(Subframe(i))；
S514 obtains subframe Subframe (i) estimated frequency shift.
Analyze and describe below in conjunction with the effect based on the spectrum estimating method of fast change Doppler channel that Fig. 6, Fig. 7, the above-described embodiment of Fig. 8 provide.
In a preferred embodiment of the invention, the Computer Simulation parameter that adopts is as shown in the table:
Table 1
Please refer to Fig. 6, be simplification system, omission scrambling, coding and synchronous, channel estimating adopts LS to estimate and linear interpolation.Suppose that the number of sub frames that the LTE transmitter sends is Frame_Num, wherein, comprise 14 OFDM symbols in each subframe, the 1st and the 8th OFDM symbol CP length are 10, and all the other OFDM symbol CP length are that 9, the 1,5,8,12 OFDM contain reference signal.
Fig. 7 has provided Doppler and has been respectively LTE performance under 0 (awgn channel), 50Hz, 00Hz, 200Hz and the 300Hz condition, and carries out the performance schematic diagram after the CIR frequency offset estimation compensation.Can draw from Fig. 8, the Doppler frequency deviation is very big to the LTE Effect on Performance, and when Doppler was 50Hz, LTE was subjected to the influence of Doppler little; When Doppler was 100Hz, signal to noise ratio was that the error rate of 20dB is 10
-6And Doppler is when being 200Hz, and signal to noise ratio is that the error rate of 20dB is 10
-2, and significantly " mistake is flat " arranged; And performance is poorer when Doppler is 300Hz.Carry out frequency deviation by CIR and estimate, can all carry out frequency offset estimation compensation to all subframes, can improve the performance of LTE greatly, especially when Doppler is big, as can be seen from Figure 7, the performance after frequency deviation is estimated levels off to awgn channel.
Fig. 8 provides the performance curve (" zero " expression) of LTE LTE when too fast change Doppler channel, because Doppler is become rapidly-700Hz by 700Hz, it is bigger that LTE is influenced by Doppler, poor-performing, " △ " expression is carried out linear frequency deviation to subframe and is estimated, can draw performance and be greatly improved, and can under lower complexity, effectively resist the fast Doppler of change.
The spectrum estimating method based on fast change Doppler channel that adopts above-described embodiment to provide, flexibly in conjunction with the fast channel characteristics that becomes Doppler's channel under the high ferro environment, the LTE signal (frame structure) that utilizes channel impulse response (CIR) that receiver is received carries out the secondary frequency deviation and estimates, and adopt linear interpolation method to calculate the frequency shift (FS) of LTE subframe, fast change Doppler when the solution correlation technique adopts simple method for synchronous that bullet train is passed through the base station carries out the coarse problem of spectrum estimation, thereby effectively improves performance and the operating efficiency of wireless communication system.
Fig. 9 is the structured flowchart based on the frequency shift estimation device of fast change Doppler channel according to the embodiment of the invention, the spectrum estimating method based on fast change Doppler channel of this device in order to realize that said method embodiment provides, this device mainly comprises: judge module 10 and computing module 20.Wherein, judge module 10, whether the numbering of second subframe that is used for judging the second subframe group is corresponding with the numbering of first subframe in the first subframe group, wherein, the first subframe group and the second subframe group are any two in the current subframe group that receives, and the subframe group is made of the subframe of predetermined number; Computing module 20, be connected to judge module 10, being used in judged result is under the situation that is, calculate the frequency shift (FS) of current other subframes except first subframe and second subframe that receive according to linear interpolation algorithm, judged result for situation not under, the frequency shift (FS) of calculating the current whole subframes that receive.
Figure 10 is that as shown in figure 10, computing module 20 can comprise: first computing module 22 is used for calculating the deviation slope between second subframe and first subframe according to the preferred embodiment of the invention based on the structured flowchart of the frequency shift estimation device of fast change Doppler channel; Second computing module 24 is connected to first computing module 22, is used for receiving the frequency shift (FS) of calculating current other subframes except first subframe and second subframe that receive according to the deviation slope.
Wherein, first computing module comprises 22: estimation unit 222, be used for according to channel impulse response CIR first subframe and second subframe being carried out estimation of deviation, and obtain the first frequency skew of first subframe and the second frequency skew of second subframe; Computing unit 224 is connected to estimation unit 222, is used for according to described first frequency skew and the described deviation slope of described second frequency calculations of offset.
The spectrum estimating method based on fast change Doppler channel that adopts above-described embodiment to provide, flexibly in conjunction with the fast channel characteristics that becomes Doppler's channel under the high ferro environment, the LTE signal (frame structure) that utilizes channel impulse response (CIR) that receiver is received carries out the secondary frequency deviation and estimates, and adopt linear interpolation method to calculate the frequency shift (FS) of LTE subframe, fast change Doppler when the solution correlation technique adopts simple method for synchronous that bullet train is passed through the base station carries out the coarse problem of spectrum estimation, thereby effectively improves performance and the operating efficiency of wireless communication system.
From above description, as can be seen, the present invention has realized following technique effect: the LTE signal (frame structure) that adopts channel impulse response (CIR) that receiver is received carries out the secondary frequency deviation and estimates, and adopt linear interpolation method to calculate the frequency shift (FS) of LTE subframe, the fast change Doppler that has solved when correlation technique adopts simple method for synchronous that bullet train is passed through the base station carries out the coarse problem of spectrum estimation, and then has reached the performance of raising wireless communication system and the effect of operating efficiency.
Obviously, those skilled in the art should be understood that, above-mentioned each module of the present invention or each step can realize with the general calculation device, they can concentrate on the single calculation element, perhaps be distributed on the network that a plurality of calculation elements form, alternatively, they can be realized with the executable program code of calculation element, thereby, they can be stored in the storage device and be carried out by calculation element, and in some cases, can carry out step shown or that describe with the order that is different from herein, perhaps they are made into each integrated circuit modules respectively, perhaps a plurality of modules in them or step are made into the single integrated circuit module and realize.Like this, the present invention is not restricted to any specific hardware and software combination.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. the frequency deviation estimating method based on fast change Doppler channel is characterized in that, comprising:
Whether the numbering of judging second subframe in the second subframe group is corresponding with the numbering of first subframe in the first subframe group, wherein, the described first subframe group and the described second subframe group are any two in the current subframe group that receives, and described subframe group is made of the subframe of predetermined number;
Be under the situation that is in judged result, calculate the frequency shift (FS) of current other subframes except described first subframe and described second subframe that receive according to linear interpolation algorithm, judged result for situation not under, the frequency shift (FS) of calculating the current whole subframes that receive.
2. method according to claim 1 is characterized in that, the frequency shift (FS) according to linear interpolation algorithm calculates current other subframes except described first subframe and described second subframe that receive comprises:
Calculate the deviation slope between described second subframe and described first subframe;
Receive the frequency shift (FS) of calculating current other subframes except described first subframe and described second subframe that receive according to described deviation slope.
3. method according to claim 2 is characterized in that, calculates the deviation slope between described second subframe and described first subframe, comprising:
According to channel impulse response CIR described first subframe and described second subframe are carried out estimation of deviation, obtain the first frequency skew of described first subframe and the second frequency skew of described second subframe;
According to described first frequency skew and the described deviation slope of described second frequency calculations of offset.
4. method according to claim 3 is characterized in that, according to channel impulse response CIR described first subframe is carried out estimation of deviation, comprising:
From described first subframe, extract the described reference signal in any two orthogonal frequency division multiplex OFDM symbols that comprise reference signal;
Obtain a CIR and the 2nd CIR of two described OFDM symbols in described first subframe respectively according to described reference signal;
According to a described CIR and described the 2nd CIR described first subframe is carried out estimation of deviation.
5. method according to claim 4 is characterized in that, obtains a CIR and the 2nd CIR of two described OFDM symbols in described first subframe respectively according to described reference signal, comprising:
Described reference signal is carried out lowest mean square LS to be estimated;
The reference signal that will obtain after will estimating through described LS transforms on the time domain;
Obtain a described CIR and described the 2nd CIR respectively according to the reference signal that transforms on the time domain.
6. method according to claim 3 is characterized in that, according to channel impulse response CIR described second subframe is carried out estimation of deviation, comprising:
From described second subframe, extract the described reference signal in any two orthogonal frequency division multiplex OFDM symbols that comprise reference signal;
Obtain the 3rd CIR and the 4th CIR of two described OFDM symbols in described second subframe respectively according to described reference signal;
According to described the 3rd CIR and described the 4th CIR described second subframe is carried out estimation of deviation.
7. method according to claim 6 is characterized in that, obtains the 3rd CIR and the 4th CIR of two described OFDM symbols in described second subframe respectively according to described reference signal, comprising:
Described reference signal is carried out lowest mean square LS to be estimated;
The reference signal that will obtain after will estimating through described LS transforms on the time domain;
Obtain described the 3rd CIR and described the 4th CIR respectively according to the reference signal that transforms on the time domain.
8. the frequency deviation estimation device based on fast change Doppler channel is characterized in that, comprising:
Judge module, whether the numbering of second subframe that is used for judging the second subframe group is corresponding with the numbering of first subframe in the first subframe group, wherein, the described first subframe group and the described second subframe group are any two in the current subframe group that receives, and described subframe group is made of the subframe of predetermined number;
Computing module, being used in judged result is under the situation that is, calculate the frequency shift (FS) of current other subframes except described first subframe and described second subframe that receive according to linear interpolation algorithm, judged result for situation not under, the frequency shift (FS) of calculating the current whole subframes that receive.
9. device according to claim 8 is characterized in that, described computing module comprises:
First computing module is used for calculating the deviation slope between described second subframe and described first subframe;
Second computing module is used for receiving the frequency shift (FS) of calculating current other subframes except described first subframe and described second subframe that receive according to described deviation slope.
10. device according to claim 9 is characterized in that, described first computing module comprises:
Estimation unit is used for according to channel impulse response CIR described first subframe and described second subframe being carried out estimation of deviation, obtains the first frequency skew of described first subframe and the second frequency skew of described second subframe;
Computing unit is used for according to described first frequency skew and the described deviation slope of described second frequency calculations of offset.
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| CN101364964A (en) * | 2007-08-06 | 2009-02-11 | 中兴通讯股份有限公司 | Frequency bias estimation method for radio communication system uplink |
| CN101630961A (en) * | 2008-07-18 | 2010-01-20 | 俊茂微电子（上海）有限公司 | Frequency bias estimation equipment, method and communication device |
| US20100080112A1 (en) * | 2008-07-11 | 2010-04-01 | Texas Instruments Incorporated | Frequency Offset Estimation in Orthogonal Frequency Division Multiple Access Wireless Networks |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101364964A (en) * | 2007-08-06 | 2009-02-11 | 中兴通讯股份有限公司 | Frequency bias estimation method for radio communication system uplink |
| US20100080112A1 (en) * | 2008-07-11 | 2010-04-01 | Texas Instruments Incorporated | Frequency Offset Estimation in Orthogonal Frequency Division Multiple Access Wireless Networks |
| CN101630961A (en) * | 2008-07-18 | 2010-01-20 | 俊茂微电子（上海）有限公司 | Frequency bias estimation equipment, method and communication device |
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| WO2021184198A1 (en) * | 2020-03-17 | 2021-09-23 | 深圳市大疆创新科技有限公司 | Frequency offset estimation method, and receiving device and storage medium |
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